umm 8 extra pipelines... that's approximately what, 20-50% higher performance depending on the conditions. as for getting a new motherboard for OCing, go for it, look into something which can support both AGP and PCI-e if you want to save money and not buy a new card.
because you would need to buy a new card, and as it is the AGP bus is more efficient given current games, it won't be for another 3-5 years before PCI-e has any advantages over AGP 3.0, atleast I was under the assumption of such, if it is not then ditch the AGP slot idea.
